Heater.



L. T. CRABTREE.

HEATER.

APPLICATION FILED Aua.2s. 191a.

Patented Apr. 27', 1915.

2 SHEETSSHEET l- 126 I I l 14 120/ 1000 .H x IIa/ WITNESSES m/mvrop jwizaiz/ fQf/Z/f'f ATTORNEYS NORRIS PETERS CO., PHOTOLITHQv WASHINGTUN, D. C.

L. T. CRABTREE.

HEATER.

APPLICATION men AUG.23, 1913.

Patented Apr. 27, 1915.

2 SHEET$SHEET 2- ATTORNEYS THE NORRIS PETERS CO.. PHDTO-LITHG-. WASHINGIDN, D. C.

LEONARD TRACY CRABTREE, OF CRANDON, WISCONSIN.

HEATER.

Specification of Letters Patent.

Patented Apr. 27, 1915.

Application filed August 23, 1913. Serial No. 786,264.

To all whom it may concern Be it known that I, LEONARD TRACY CRABTREE, a citizen of the United States, and a resident of Crandon, in the county of Forest and State of Wisconsin, have invented a new and Improved Heater, of which the following is a full, clear, and exact description.

7 The present invention is designed to provide a heater having the maximum heating capacity in proportion to the fuel consumption.

A further design of the invention is to provide a heater that can be utilized for effectively ventilating a room or rooms.

The invention further has for its design to provide a heater having an improved heat-insulating casing.

The invention will be particularly explained in the specific description following.

Reference is to be had to the accompanying drawings forming a part of this specification, in which similar characters of reference indicate corresponding parts in all the views, and in which- Figure 1 is a vertical section of a heater embodying my invention; Fig. 2 is a front elevation partly in section; Fig. 3 is a sectional plan view.

In constructing a heater in accordance with my invention, an outer casing is provided, comprising an exterior shell 10 and an inner shell 11, both being formed preferably of sheet metal, a layer 12 of asbestos around the inner shell, and a layer 12 of pulp around the layer of asbestos, the two metallic shells inclosing the said layers. The construction of the casing is designed to afford the maximum heat-insulating qualities. The casing is supported on suitable legs 13, and it is L-shaped, consisting of a horizontal body 14- and a vertical member 15.

l/Vithin the horizontal portion 14, a tubular fire-box 16 is disposed, concentric with and spaced from the outer casing. An uptake 17 extends from the rear end of the fire-box and communicates at its upper end with a'tubular outlet 17 which'may lead to a chimney.

Surrounding the ,fire-boxbetween the same and the outer casing-is awspiral air flue 18, and, similarly, a spiral flue 19 surrounds the up-take 17 and communicates with the flue 18. Leading to the spiral flue 18 is an inlet pipe 20 extending to the exterior of the heater, the inlet, in practice, extending to the exterior of the building or to a fresh air space below the floor, thereby to afford an ample supply of fresh air to the fines 1819, to be heated. There is a lateral branch inlet 21 to the main fresh air inlet 20, at a point immediately adjacent to the heater, and preferably beneath the same, so as to be located adjacent to the floor Act the room.

Dampers. 22 and 23, of any approved form are provided in the main inlet 20 and branch inlet 21, either of which dampers may be opened or closed. If the damper 23 be closed and the damper 22 opened, fresh air may freely enter through the spiral air flues, through the main air inlet 20. On the other hand, if the damper 22 be closed and the damper 23 be opened, air will be taken in through the branch inlet 23, to be again heated and discharged at the top of the heater. The provision of the branch inlet is for the purpose of heating the air in a room with a minimum expenditure of fuel. In fact when the fire-box and air flues have been thoroughly heated, the insulated casing conserves the heat so that without any further expenditure of fuel, the air may be continuously taken in through the branch inlet and again discharged, thus fully utilizing the hot elements of the heater without admitting fresh air from the outside to cool the same.

- At the top of the spiral flue 19 of the uptake, an air chamber is produced by vertically spaced horizontal plates or partitions 24 having openings 25 for the outlet of the air. The provision of the hot air chamber above the spiral flue 19 will result in the air therein being highly heated and tend to induce the flow of air through the air flues. Above the upper partition 24 a flaring deflector 26 is provided around the tubular outlet 17' of the up-take, the said deflector being spaced from the top of the heater casing and serving to deflect the out-flowing air in everydirection. v

, The front 27 of the heater'is formed similarly tothe described outer casing of the fire-box and up-take,,havi ng the inner and outer shells 11, thellayer 12? corre-, sponding with thelayer" 12, and'the layer 12 of pulp corresponding with the layer 12 The front is provided With anopening 28 leading to the fire-box, and with "a fire tutes an inner end grate, there being suit able openings in said transverse member.

In order that the heater may constitute a ventilator, I providean air inlet 34 which extends inwardly through theouter casing, through the intermediate air flue 18 and through the wall of the fire-box 16 to the in-- terior of the latter. The inlet is provided with a suitable damper 35 and the outerend is close to the bottom of the heater and hence will be-close to the floor of a room, soithat when the. damper 35 is open, the contaminated air near the floor will pass into the fire-box and be discharged through the outlet '17 thereby'eflectively ventilating the room since fresh air maybe admitted continuously through theinlet 20 and flues Below the grate a suitable ash box 36 is constructed, to receive an ashi pan, to be inserted through the. opening 30, It will thus be seen that avery effective heater is provided which may be readily'converted into a ventilator. It is to b e understood that when there is no fire in the grate and it is desired to ventilate, a gas jet or lamp may furnishthe necessary heat for inducing the ventilating current through "the ventilating inlet 34:. p i v That the results obtained by my improved heater, and its advantages may be the better understood, I would explain that the described construction is highly eflicient in maintaining'a room at a given temperature after the room has been initially heated by the heater. Assuming that the room has been heated to, say, 70 F., and the spiral flue and fire boxto be at a higher heat than the airin the room, from an initial consumption of fuel, then by shutting the draft openings and charging the heater with fuel,

the consumption of the fuel will be very slow, as will be obvious, and at the same time the heat ofthe fuel and adjacent metal parts will, owing to the insulated covering,

part with theirheat only to the hea ted air of the room being circulated through the flues. Inasmuch as the air of the room is itself already heated, it will in passing through the fines deprive the latter of but little heat to maintain the temperature of the air in the room, and thus the heater Wlll serve to maintain the room in a heated con- 7 dition with the least possible consumption of fuel, v

I do not wish to be understood as claima horizontal spiral flue per se, nor as claiming a spiral up-t'ake flue per se;

Neither the one nor the other will suffice" V to maintain a room heated in the manner I describe, for the reason that it is impractical to provide a horizontal flue of sulficient length to be efiicient with the drafts of'the stove closed, and it is impossible also, in any ordinary room, to construct a separate up-take aloneof a lengthto-be efficient. In fact, the spiral up-take if employed alone, will, in. practice, lose the-greater' part of its: heat to the air at the-bottom of the'fiue, and the-upper'end of-"thevflue will remain comparatively cool. -I have found that a horizontal flue combined with a communicating up-take flue, both spiral, can be given in a'comparatively small stove, a total effective: length of thirty feet or more, and by'combining'the two, I can maintain a comfortable. temperature in a comparatively small dimensions; v

The combined use of the inner layer of asbestos or equivalent non-combustible, heatr,

"room, even in cold weather, by a heaterlof take forming an upward continuation of v r the horizontal fire box, a-spiral air flue surrounding the fire box,and a communieating spiral air fluesurroun'ding the tubular up-take, the spiral flue of the horizontal fire box having an inlet 7 adjacent} to the front of the heater, to permit 'air to'enter said flue from the room in whichthe stove is located, and there being an outlet for the air at the upper'end of the spiral air tube of the up-take. Q a

2. A heater having an approximately horizontal 'fire' box and a communicating up-take, the fire box and uptake having communicating airsheating flues surrounding' said fire-box and up-take, there being an inletto the air flue of the fire box near I i the front of the'heaten' 'iand an outlet for the air at the upper end of the of the up-take, the said air flues having a casing In testimony whereof I have signed my comprising a metallic inner Wall, a layer name to this specification in the presence of 10 of non-combustible, heatinsulatindg mziifteria two subscribing Witnesses.

directy applied to the outer si e 0 sai r wall a layer formed of Wood pulp applied LEONARD TRACK GRABTREE' to said layer of non-combustible material, Witnesses:

and a sheet metal inclosing shell around M. HAUGAARD,

said layer of Wood pulp. a M. L. SGHENOK.

C'opies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents. Washington, D. G. 

